Method and apparatus for manufacturing of a brush ring

ABSTRACT

The invention relates to a method for manufacturing of a brush ring, whereby the brush ring is intended to be used particularly with several corresponding brush rings as a brush, that rotates around a longitudinal axis, in a brushing machine. The brush ring consists of a brush part ( 1 ) and a ring shaped frame part ( 2 ), that connects the radially directed (r) brushes ( 1   a ) forming the brush part ( 1 ), which parts ( 1, 2 ) are formed as a uniform entirety preferably from plastic based material, and in which there has been arranged at least holding means ( 3 ) to prevent the brush ring from twisting, when the same has been assembled in place to the brush frame of the brushing machine. The brush ring is being manufactured from an essentially elongated brush preform ( 1 ′), in which the brushes ( 1   a ) are connected to each other by melting ( 1 &#39;s), wherein on the melting ( 1 &#39;s) existing at the top edge of the brush preform ( 1 ′), that moves along in an essentially upright position, plastic paste ( 2 ′), is being led, that is in an essentially solid state, to work the brush ring to its final shape by means of a press mold assembly (X) by forming the frame part ( 2 ) and preferably the holding means ( 3 ) from the said plastic paste ( 2 ′). The plastic paste ( 2 ′) is being led bent in a ready finished shape, such as through a U-shaped extrusion groove (U) or correspondingly, on top of the melting edge ( 1 &#39;s) of the brush preform ( 1 ′), that is as an advantageous embodiment being preheated in the same connection. The invention relates to an apparatus, also, that operates according to the method.

FIELD OF THE INVENTION

The invention relates to a method for manufacturing of a brush ring,whereby the brush ring is intended to be used particularly with severalcorresponding brush rings as a brush, that rotates around a longitudinalaxis, in a brushing machine. The brush ring consists of a brush part anda ring shaped frame part. The frame part connects the radially directedbristles forming the brush part. The frame and the brush parts areformed as a single member uniformly from plastic based material. In theframe part there has been arranged at least holding means to prevent thebrush ring from twisting, when the brush ring has been assembled inplace to the brush frame of the brushing machine with the other brushrings placed one after another in the longitudinal direction. The brushring is manufactured from an essentially elongated brush preform, inwhich the bristles are connected to each other by melting bristlestogether at one end to form a melted edge. On the melted edge existingon top of the brush preform, that moves along in an essentially uprightposition, plastic paste is fed in. The plastic paste is in anessentially solid state, to enable the brush ring to be worked to itsfinal shape by means of a press mold assembly by forming the frame partand preferably the holding means from the plastic paste.

BACKGROUND OF THE INVENTION

The type of brush rings described above are used to form brushes indifferent kinds of sweeping trucks and brushing machines. The brushrings being used today usually comprise a ring shaped frame part. Inother words, the frame part has been formed to a circumferential shapewhen viewed from the side. The ring shaped frame part is usually made ofthin sheet iron, the thickness of which is, for example, about 1 mm. Thebristles have been attached to this kind of frame part, for example, bymeans of a suitable solidifying attachment mass. This type of brush ringis usually planar.

This type of brush ring, that is partly made of metal, tends to breakparticularly because of cold, which causes stiffening of the brushes. Onsuch an occasion, the frame sheet iron supporting the brush part of thebrush ring opens in certain places, in which case bigger or smallerunits of brush parts are released from the brush ring. In addition tothe foregoing problem, it is practically impossible to re-use brushrings with metal frames and plastic brushes, because removing the framesheet iron from the brushes is not economically justified in practice.That is why this type of brush ring is removed as a whole to the dumpingarea. That is naturally a significant waste problem. Furthermore, whenthe type of brush rings described above are being used, very stronglybuilt supporting structures must be used, also, such as space rings madeof metal, fastening rings etc., which is why a brush formed of this kindof brush rings becomes disproportionately expensive.

On the other hand from Finnish Patent No. 87977, a brush element ispreviously known, that is entirely made of plastic based material. Whenapplying the method according to the afore-mentioned patent, plasticpaste existing essentially in a solid shape is fed onto the melted edgeexisting at the top edge of the brush preform, that moves along in anessentially upright position, to work the brush ring to its final shapeby means of a press mold assembly by forming the frame part andpreferably the holding means from the plastic paste. However,arrangements explained in Finnish Patent No. 87977 in particular forfeeding the plastic paste on top of the melted edge of the brush preformare insufficient when being carried out in practice. This leads to theplastic paste becoming unevenly distributed on the brush preform. Thisleads furthermore to the result that, when pressing the brush preform tobring out a final brush ring, the final brush ring is not adequately ashomogeneous. This results in many significant disadvantages in practice,when the brush ring is being used in a brushing machine, wherein, forexample, vibration is caused due to unbalance. Furthermore, due to theabove-noted extra wearing of the brushing machine, discomfort in the useof the machine is caused as well. Furthermore, the brush elements beingmanufactured by the method described in the patent above are planar.Thus, due to wearing of the brushes, the brushing of the brush formed ofthe brush rings becomes discontinuous in the longitudinal direction ofthe brush, particularly in the jointing points of the brush rings.Therefore, the brush is not able to fulfill, to a satisfactory extent,conventional demands that are requested in certain purposes, becausematerial to be brushed may go through the brush without touching thebristles, in which case the brush must be dismantled and the brush ringsreplaced.

SUMMARY OF THE INVENTION

It is the aim of the method for manufacturing of a brush ring accordingto the present invention to achieve a decisive improvement in theproblems presented above and, thus, to essentially raise the level ofknowledge in the field. To achieve this aim the method according to thepresent invention is primarily characterized in that the plastic pasteis fed out formed into a ready finished shape, such as through aU-shaped extrusion groove or the like, onto the brush preform,preferably on top of a melted edge of the brush preform, that is beingsimultaneously preheated.

Among the most important advantages of the method are simplicity andreliability. Thanks to the invention, it is possible to produce brushrings, the manufacturing costs of which are significantly moreprofitable and that are more homogeneous than present brush rings. Inparticular the forming of the plastic paste into a desired shape inadvance improves significantly homogeneity of the brush rings, becausethe plastic paste forming the frame part is prevented from beingunevenly distributed. Thanks to the invention, the brush ringsmanufactured by this method are both very user-friendly and durable,particularly due to their homogeneity. When exploiting advantageouslypreheating of the brush preform, the method according to the inventionfurthermore assures that the contact between the solid melting pasteconnecting the brush preform and brush ring to each other is achievedreliably and effectively when the plastic paste is extruded on the brushpreform. The preheating described above also causes roughness of themelted edge of the brush preform to be balanced by influence of heating,which furthermore enables a contact as even as possible between themelted edge and the plastic paste.

Advantageous embodiments of the method according to the invention aredescribed below.

The invention relates to an apparatus functioning according to theprinciple of the method as well, that is being described in a greaterdetail below.

The most important advantages of the apparatus according to theinvention include simplicity and reliability of its construction anduse. By very simple arrangements, for example, when advantageouslypreheating the brush preform during extrusion, it is possible to achievea uniform and continuous contact between the melted edge of the brushpreform and the plastic paste to be extruded on it. The brush ringsmanufactured by the apparatus are particularly homogeneous, due to theextrusion groove existing in the extrusion device belonging to theapparatus. The shape of the groove corresponds to the shape of the brushpreform and places the plastic paste in a ready formed shape on thebrush preform, thereby preventing it from being unevenly distributed.The brush rings manufactured by the apparatus according to the inventionhold together particularly well due to contact between the plastic pasteforming the frame part and the brush preform forming the brush partbeing sufficiently efficient due to preheating. Accordingly, the brushrings manufactured by the apparatus, in addition to being homogeneousare also durable due to a strong structure. It is advantageous to usethe apparatus according to the invention particularly in connection witha brush ring, in which the touching point of the outer radial edge ofthe brush part of the brush ring has an effect within the whole width ofthe brush ring, to achieve an essentially unbroken brush touch in thelongitudinal direction of the brushing machine to the object beingbrushed continuously regardless of the length of the bristles, when thebrush rings forming the brush keep rotating around the longitudinalaxis. The brushing result of this type of zig-zag brush ring remainsoptimal with a respect to brushing effect despite wearing of thebristles significantly longer than with currently utilized planar brushrings. That means, in principle, until the bristles wear out.

Advantageous embodiments of the apparatus according to the invention aredescribed below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following description, the invention is illustrated in greaterdetail with reference to the appended drawings, in which

FIGS. 1a and 1 b show sectional side views of a brush formed ofconventional brush rings as after brief use (a) and after heavy use (b),

FIG. 2 shows a perspective view of an advantageous brush ring accordingto the present invention,

FIG. 3a shows a front view of manufacturing of the brush ring shown inFIG. 2,

FIG. 3b shows a cross-sectional view of a portion of the brush ring, asseen along lines 3 b—3 b of FIG. 3a;

FIGS. 4a and 4 b show, respectively, a front view and a side view of anextrusion frame of an apparatus applying the method according to theinvention, and

FIGS. 5a and 5 b show advantageous counterpart surface arrangements ofan apparatus applying the method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a method for manufacturing of a brush ring. Thebrush ring is intended to be used particularly with severalcorresponding brush rings as a brush, that rotates in a direction waround a longitudinal axis s, in a brushing machine. The brush ringconsists of a brush part 1 and a ring shaped frame part 2, that connectsthe bristles 1 a radially directed in a direction r and forming thebrush part 1. Parts 1, 2 are formed, preferably, as a single memberuniformly from plastic based material. In the frame part 2 there hasbeen arranged at least holding means 3 to prevent the brush ring fromtwisting, when the parts have been assembled in place to the brush frameof the brushing machine.

As shown in FIGS. 4a and 4 b, the brush ring is manufactured from anessentially elongated brush preform 1′. The bristles 1 a are connectedto each other by melting together ends of the bristles 1 a to form amelted edge 1's. Upon the melted edge 1's existing on top of the brushpreform 1′, which moves along in an essentially upright position,plastic paste 2′ in an essentially solid state is advanced. The brushring is worked to its final shape by means of a press mold assembly X byforming the frame part 2 and preferably the holding means 3 from theplastic paste 2′. The plastic paste 2′ is advanced formed into a readyfinished shape, such as through a U-shaped extrusion groove U or thelike, on top of the melted edge 1's of the brush preform 1′. The brushpreform 1′ is advantageously preheated.

As a particularly advantageous embodiment, the extrusion device 4 thatfeeds solid plastic paste 2′, such as an extruder or the like, comprisesa heated and an essentially elongated extrusion frame 4 a. Inside offrame 4 a the brush preform 1′ is advanced through a passage duct 4 a′existing therewith, particularly for preheating of the melted edge 1'sof the brush preform 1′ before extruding the plastic paste 2′ on it.

The principle described above may be observed particularly from FIGS. 4aand 4 b, which show an extrusion frame of an extrusion device applyingthe method according to the invention as a front view and a side view.Furthermore in the advantageous brush rings shown in FIGS. 2 and 3a,principles of the applicants previous Finnish patent application FI963433, “Harjakiekko” have been adapted.

As shown in FIG. 2, the frame part 2 of the brush ring has anessentially constant cross section. The frame part 2 undulates in awave-type form having at least a lower level o and an upper level x. Theupper level x is displaced from the lower level o in a direction s. Athree-dimensional press mold assembly X, shown in FIGS. 5a and 5 b, maybe used to form the frame part 2 into the described shape. The pressmold assembly X has press molds X1. In an advantageous embodiment,surfaces of the press molds X1 that come into contact with the framepart 1 and brush part 2 during formation of the brush ring have fourprojections for forming portions of the ring on the x level, to one sidesi of the lower level o, as shown in FIG. 3b.

When comparing a known brush, as shown in FIGS. 1a and 1 b, and itsfunction with a brush formed of brush rings according to the inventionand its function, it may be observed that the brush ring according tothe invention may be used in principle as long as an adequate brushingeffect may still be obtained with the bristles. When coupling knownbrush rings, space collars are always needed in principle between thebrush rings placed one after another. This points out furthermoreunsatisfactory functioning of known planar brush rings in the respectthat, due to wearing of the bristles, with reference particularly toFIG. 1b, the brushing surface presented by the outer radial edge of thebrush very quickly becomes discontinuous. For example, the brush shownin FIG. 1b would not be useable any more for most usual purposes.Similarly, the brush shown in FIG. 1a would already be nearlyunsatisfactory for certain especially demanding purposes.

Furthermore as an advantageous embodiment of the method, the entirebrush ring, including the bristles 1 a forming the brush part 1 and theplastic paste 2′ forming the frame part, may be manufactured fromrecyclable and preferably essentially the same manufacturing material,such as polypropylene.

Furthermore as an advantageous embodiment, the width of the plasticpaste 2′ extrusion is adjusted to correspond essentially to the width ofthe brush preform 1′ of each brush ring to be manufactured by usingextrusion frames 4 a having, for example, interchangeable extrusiongrooves U and/or passage ducts 4 a′ with different dimensions.

The apparatus for manufacturing the type of brush rings described abovecomprises, thus, at least an extrusion frame 4 a to feed plastic paste2′, formed into a ready finished shape, such as through a U-shapedextrusion groove U or the like, on the brush preform 1′, that ispreferably preheated. After extrusion, the brush ring may be worked toits final shape between the press mold assembly X to form both the framepart 2 and advantageously the holding means 3 as well from the plasticpaste 2′.

As an advantageous embodiment the extrusion device 4 feeding solidplastic paste 2′ comprises a heated and particularly with reference toFIG. 4b, an essentially elongated extrusion frame 4 a, to guide thebrush preform 1′ inside the same through a passage duct 4 a′,particularly for preheating the melted edge 1's of the brush preform 1′before extruding the plastic paste 2′ on it. As an advantageousembodiment, the extrusion groove U and/or the passage duct 4 a′ of theextrusion device 4 are connected removably to the extrusion frame 4 a,to adjust, for example, the width of the extrusion and/or of the passageduct to correspond essentially to the width of the brush preform 1′ ofeach brush ring to be manufactured. Furthermore, with referenceparticularly to FIG. 4a, the extrusion frame 4 a has a passage duct 4 a′at its bottom, the width of which corresponds essentially to the widthof the brush preform 1′, when viewed in a cross section as shown in FIG.4a. Furthermore, with reference to FIG. 4b, at the extrusion end I ofthe extrusion frame 4 a, the extrusion groove U existing thereinsurrounds the passage duct 4 a′.

Furthermore, as an advantageous embodiment, the brush ring has beenworked to its final shape by means of the press mold assembly X, wherebythe holding means 3 are formed simultaneously, when the frame part 2 isbeing pressed to the press mold assembly X, by means of a counterpartsurface arrangement 6 existing in the press mold assembly X, whereby theholding means 3 are formed by means of material spreading from the framepart 2 thereto during pressing. The counterpart surface arrangement 6 isa unit, that is connected removably to the press mold assembly X,particularly for preparing brush rings with differing holding means 3 byreplacing only the counterpart surface arrangement 6 and otherwise usingone and the same press mold assembly X.

Furthermore as an advantageous embodiment of the invention, thecounterpart surface arrangement is intended particularly formanufacturing of a brush ring that comprises an essentiallycircumferential frame part 2, when viewed from the side, in which casethe holding means 3 comprises at least one shoulder arrangement 3 aexisting therewith and, whereby the brush part 1 and the frame part 2are entirely made of recyclable and preferably essentially of the samemanufacturing material, such as polypropylene. With reference to theembodiments shown particularly in FIGS. 3a, 5 a and 5 b, the counterpartsurface arrangement 6 has been attached removably, preferably, to thelower press mold X1 of the press mold assembly X, preferably by means ofa quick locking principle, such as by means of a form locking joint,screw joint 5 and/or the like.

With reference particularly to the advantageous embodiment shown in FIG.3a, the counterpart surface arrangement 6 is carried out by aninterchangeable counterpart piece 6 a, that is placed essentially at thepoint of the holding means 3 in the press mold X1. Furthermore as anadvantageous embodiment, the counterpart surface arrangement 6 may bearranged, i.e., implemented, by one uniform interchangeable counterpartsurface existing in the press mold X1, that is, for example,continuously pressed against the frame part 2 in the radial direction.Such a uniform interchangeable counterpart surface may be formed, asshown in FIG. 5a, of a uniform circular ring 6 a′, and as shown in FIG.5b of, for example, an essentially uniform planar interchangeablecounterpart plate 6 a″. The essentially uniform planar interchangeablecounterpart plate 6 a″ may be attached to a surface of the press mold.The surface of the press mold may be essentially planar.

It is obvious, that the invention is not limited to the embodimentspresented or described above, but it can be modified within the basicidea even to a great extent. In this case, it is first of all possibleto form the type of brush rings described above of a frame part, thatis, for example, wider than described above and into which there hasbeen attached, for example, one single spiral-shaped brush part that hasbeen implemented by means of a two or multiple ended threading. It isalso possible to exploit the principle described above on the other handby using a solution like the one shown in FIG. 2, in which the framepart comprises a structure, that has, for example, knees extendingsidewards instead of a structure having a constant cross section. It isalso possible to equip the brush rings according to the invention withauxiliary holding arrangements, functioning, for example, on themale-female-principle and that are placed at the axially directed sidesurfaces of the frame parts in the brush ring, in which case auxiliarycounterpart surface arrangements for the above are naturally needed. Itis naturally possible to produce a brush ring according to the inventionfrom most heterogeneous materials, by exploiting most heterogeneousmanufacturing methods. In the foregoing description, use ofpolypropylene as the manufacturing material of the brush rings has beenrepresented as only one example, that is, however, a very suitablealternative in this context.

What is claimed is:
 1. A method for manufacturing a brush ring that isto be used with a plurality of similar brush rings as a brush thatrotates around a longitudinal axis in a brushing machine, the brush ringcomprising a brush part formed of radially directed bristles and a ringshaped frame part that connects the bristles, the brush part and theframe part being formed as a single member and including holding meansfor preventing the brush ring from twisting when the plurality of brushrings have been assembled one after another in a longitudinal directionon a brush frame of a brushing machine, the method comprising: providingan essentially elongated brush preform in which the bristles areconnected to each other at one end; feeding plastic paste in anessentially solid state onto said one end of the bristles at a top edgeof the preform, the plastic paste being fed in a finished shape; andworking the brush ring to a final shape utilizing a press mold assemblyto form at least the frame part from the plastic paste.
 2. The methodaccording to claim 1, wherein the plastic paste is fed on the preform asthe preform moves along in an essentially upright position.
 3. Themethod according to claim 1, wherein the bristles are connected to eachother by melting.
 4. The method according to claim 3, wherein theplastic paste is fed on top of the melted bristles.
 5. The methodaccording to claim 4, further comprising: preheating the preform priorto feeding the plastic paste.
 6. The method according to claim 1,wherein the plastic paste is applied with an extrusion device that feedsthe plastic paste bent in a finished shape.
 7. The method according toclaim 6, wherein the plastic paste is fed through a U-shaped extrusiongroove.
 8. The method according to claim 6, wherein the extrusion deviceis an extruder.
 9. The method according to claim 6, wherein theextrusion device comprises a heated and essentially elongated extrusionframe including a passage duct through which the brush preform is fedfor preheating the melted bristles before extruding the plastic paste onthe preheated melted bristles.
 10. The method according to claim 9,wherein the extrusion frame is removably connected to the extrusiondevice and comprises a variable size passage duct having a shapeadjustable to correspond to a width of the brush preform.
 11. The methodaccording to claim 1, further comprising: preheating the preform priorto feeding the plastic paste.
 12. The method according to claim 1,wherein working the brush ring also formed the holding means from theplastic paste.
 13. An apparatus for manufacturing a brush ring that isto be used with a plurality of similar brush rings as a brush thatrotates around a longitudinal axis in a brushing machine, the brush ringcomprising a brush part formed of radially directed bristles and a ringshaped frame part that connects the bristles, the brush part and theframe part being formed as a single member and including holding meansfor preventing the brush ring from twisting when the plurality of brushrings have been assembled one after another in a longitudinal directionon a brush frame of a brushing machine, wherein the brush ring ismanufactured from an essentially elongated brush preform in which thebrushes are connected to each other at one end, the apparatuscomprising: an extrusion device including an extrusion frame for feedingplastic paste in an essentially solid state on the joined together endof the bristles, wherein the plastic paste is arranged to be led bent ina ready finished shape; and a press mold assembly for working the brushring to a final shape by forming at least the frame part from theplastic paste.
 14. The apparatus according to claim 13, wherein theextrusion frame comprises a U-shaped extrusion groove through which thebrush preform is fed.
 15. The apparatus according to claim 13, whereinthe extrusion device preheats the melted end of the bristles prior tofeeding the plastic paste on the melted end of the bristles.
 16. Theapparatus according to claim 13, wherein the brush preform travels in anessentially upright position through the extrusion device, the extrusionis arranged on top of the melted end of the bristles to feed the plasticpaste on the top of the melted end of the bristles.
 17. The apparatusaccording to claim 13, wherein the press mold also forms the holdingmeans from the plastic paste.
 18. The apparatus according to claim 13,wherein the extrusion device is an extruder.
 19. The apparatus accordingto claim 13, wherein the extrusion frame is heated and essentiallyelongated and comprises a passage duct that the brush preform is fedthrough, the melted end of the bristles being preheated by passingthrough the heated extrusion frame before extruding the plastic paste.20. The apparatus according to claim 19, wherein the apparatus comprisesextrusion frames that are removably connected to the extrusion deviceand that have mutually differing extrusion grooves and/or passage ductsfor adjusting a shape of the extrusion grooves and/or the passage ductsto correspond to a width of the brush preform.
 21. The apparatusaccording to claim 13, wherein the apparatus comprises extrusion framesthat are removably connected to the extrusion device and that havemutually differing extrusion grooves and/or passage ducts for adjustinga shape of the extrusion grooves and/or the passage ducts to correspondto a width of the brush preform.
 22. The apparatus according to claim21, wherein the extrusion frame comprises an extrusion groove arrangedat an extrusion end of the extrusion frame, wherein the extrusion groovesurrounds the passage duct.
 23. The apparatus according to claim 13,wherein the extrusion frame comprises a passage duct at a bottom of theextrusion frame, a breadth of the passage duct corresponding essentiallyto a cross-sectional breadth of the brush preform.
 24. The apparatusaccording to claim 13, further comprising: a counterpart surfaceremovably connected to the press mold assembly for manufacturing brushrings with different holding means by rearranging the counterpartsurface.
 25. The apparatus according to claim 24, wherein thecounterpart surface is removably attached to a lower press mold of thepress mold assembly.
 26. The apparatus according to claim 24, whereinthe counterpart surface is removably attached to the press mold assemblywith a quick locking principle.
 27. The apparatus according to claim 26,wherein the quick locking principle comprises a form locking jointand/or a screw joint.
 28. The apparatus according to claim 24, whereinthe counterpart surface is attached to the press mold assembly with aninterchangeable counterpart piece that is placed essentially at theholding means.
 29. The apparatus according to claim 24, wherein thecounterpart surface is arranged by a uniform interchangeable counterpartsurface in the press mold that is continuously against the frame part ina radial direction.
 30. The apparatus according to claim 29, wherein theinterchangeable counterpart surface is arranged by a uniform circularring in a longitudinal direction.
 31. The apparatus according to claim29, wherein the interchangeable counterpart surface is arranged by auniform planar structure to be attached against an essentially planarpress mold surface.
 32. The apparatus according to claim 31, wherein theuniform planar structure comprises a plate or sheet.